Methods for operating a combustion engine which has a mass-flow line in the form of an exhaust branch and in which at least one component effecting a pressure drop is arranged in the exhaust branch, e.g., a turbine of an exhaust turbocharger, and/or a catalytic converter, are already known. In this context, it is also known that a first pressure can be measured with the aid of a first pressure sensor upstream from the turbine, and a second pressure in the exhaust branch can be measured with the aid of a second pressure sensor downstream from the turbine or downstream from the catalytic converter.
Currently, only limited measures are known to monitor the two pressure sensors in the exhaust branch. At very low engine speeds, or when the engine is turned off, the sensor values of the two pressure sensors are easy to compare with one another since the pressure differential between the first pressure sensor and the second pressure sensor is negligible. For other operating points, e.g., at greater rotational speeds, there are rough estimation methods for the monitoring of the pressure sensors which, however, do not consider the actual loading of a particle filter in the exhaust branch, in particular.